5. Infecting Damian With Joker Venom & Making Him Fight "Batman" (Batman and Robin Vol. 2 #15-16)
As part of a tie-in comic to the previously mentioned Death of the Family story arc in which Alfred Pennyworth was kidnapped, Damian Wayne decided to go looking for Batman's butler himself. Starting at the scene in Wayne Manor where the kidnapping took place, Damian used his dog, Titus, to lead him to Gotham Zoo. At Gotham Zoo, he was attacked by Hyenas which infected him with Joker Venom and weakened him. Joker then told Damian he was going to force him to fight his father - who had been brainwashed using a Joker toxin - to the death. Joker set Batman on to him and the two fought - albeit it very much to Robin's chagrin - until Robin decided that he would rather die at his father's hands than kill him. At that point, the Joker activated a fail-safe that killed Batman - only to reveal that it was an imposter. Putting Damian through that is one thing, but the guilt that this must have made Batman feel is another thing entirely.
